#1Remove Doubles

Firstly let's check how heavy the scene is in the green rectangle (turn on Statistics in Viewport Overlays in the header). Select what objects you want to clean. I am selecting all objects. In the Properties panel on the right, find Object Properties (orange square icon). After successful installation, you will see the Cleaner panel there. Click Remove Doubles. This action removes duplicate vertices. When the operation is finished, you can compare the number of vertices - it is almost one-half of the original.

Merge Distance can be adjusted right after the operation via Adjust Last Operation (F9). Default 0.001 m.

#2Clear Custom Split Normals

Every model imported from Rhino (and many other software) has Custom Split Normals on every object. This attribute causes problems with correct shading. Now it looks almost right, but it is not. So let's select the desired objects and click Clear Custom Split Normals. The result shows us the real state of the model. Now we can see that there is a problem with flipped normals.

NOTE  Default Blender clears custom split normals only on the active object. Cleaner does it for all selected objects at once.

#3Unify Normals

Turn on Face Orientation in Viewport Overlays (header). You can see how messed up the normals are. Blue is correctly oriented outwards, red is oriented inwards. We are not inside the geometry itself, so everything should be blue. Select all objects and press Unify Normals. This step applies "Recalculate Outside" for every selected object at once.

NOTE  Surfaces without thickness can be flipped anytime, because it is impossible to determine the required normal direction.

#4Clean Unused Materials

Very often, objects contain a lot of material slots that they are not using anymore. When a model is divided into smaller parts and layers, every material used in the past remains in the panel on all objects. In the end, you can have a confusing environment with many materials on an object that uses only one. Select any number of objects and press Clean Unused Materials.

#5Limited Dissolve

Some similar cleaning applications present the output after this command. It looks perfect. The problem is that faces are still triangulated, you just dissolve many vertices with edge lines. Topology has changed. When you hit Ctrl + T for Triangulate, you see less vertices connected differently. Planar surfaces work almost every time, but in some cases this command causes geometry problems because of the lack of vertices describing the shape. I usually find out after a longer time, when I render. What I am doing then is looking for the original mesh and repeating the process. That's why I recommend being careful with this one, and I use it almost every time separately with enough attention. But it looks great :)

Faces with different materials are never merged. Max Angle can be adjusted via Adjust Last Operation (F9). Default 5°.

Congratulations! Now your 3D model is much lighter. Workflow could be faster. The size of the model is also smaller.

But even better news is that the real Cleaner starts from here :)

#6Geometry

Clear Custom Split Normals + Remove Doubles + Unify Normals

As you guess, these buttons run more commands at once. The first one is a basic pack for fundamental cleaning.

#7Geometry + Materials

Clear Custom Split Normals + Remove Doubles + Unify Normals + Clean Unused Materials

The medium way of cleaning. This setup doesn't change any topology, models look the same but much lighter and cleaner. We prefer this setup for most cases.

#8Geometry + Materials + Dissolve

Clear Custom Split Normals + Remove Doubles + Unify Normals + Limited Dissolve + Clean Unused Materials

Lastly, we have the most powerful cleaning combination. With this setup, you will get the lightest output. For the reasons I wrote before, I am using this one only for special occasions.

AImport data from other software

The add-on works as a simple tool for quickly cleaning models as the first step after importing data.

BBigger offices

After working for a company with more than 40 employees, I can say that software eclecticism is a normal situation. More departments means more specializations and more software to use. On the other hand, time requirements are often very strict and short. In that situation every minute is valuable. And of course, when you can work with clean data instead of a triangulation disaster, it is nice to have every day.

CArchitecture

Architecture is a perfect example of a field where the add-on is useful daily. The advantage is editing many data at once. Every work with urban models involves a large number of building objects, and very often the building geometry is broken. It would be a very painful type of work to repair the buildings manually one by one. Cleaner makes a chain of operations for all objects with one button. When focusing on detail, the add-on can be useful when inspecting any systems with multiple objects such as facade cladding, floor planks, or fence fillings. Data from the construction department often come from BIM software like Revit, Allplan and Archicad, while architects use fast and dirty visions in SketchUp. A situation that looks 3D-like after an explosion is absolutely common.

D3D printing

When converting a model to printable, the essential requirement is the removal of duplicates and the correct direction of normals. That's why the add-on can be suitable for the basic preparation for 3D printing.

Workflow: Batch operators renamed to Geometry, Geometry + Materials and Geometry + Materials + Dissolve. Each name now shows exactly what it runs.
Workflow: Clear Custom Split Normals added to all batch operations.
Settings: Merge Distance and Max Angle can be adjusted after running an operator (Adjust Last Operation, F9). Defaults unchanged (0.001 m, 5°).
Logic: Limited Dissolve no longer merges faces with different materials.
Logic: Geometry + Materials + Dissolve now dissolves before cleaning materials, so no unused slots are left behind.
Logic: Operators return to Edit Mode when started from it. Active object stays unchanged.
Logic: Hidden geometry is now included. Shared mesh data is processed only once. Linked library meshes are skipped.
UI: Buttons are disabled when no editable mesh is selected, with a tooltip explaining why.
UI: The status report now shows actual results (merged vertices, dissolved faces, cleared normals, removed material slots).
Core: Geometry processing rewritten with BMesh. One pass per mesh, no mode switching. Much faster with many objects selected.

Workflow: Operators renamed to Repair Geometry, Prepare Asset, and Sanitize Mesh.
Logic: Added safety checks for objects without materials (prevents batch operation errors).
UI: Implemented boxed layout with native icons and standardized tooltips.
Core: Complete code refactor for improved stability and performance.

IMPORTANT  Migrated to the Blender Extensions system (4.2+). Internal IDs updated. Uninstalling the legacy version is required to prevent conflicts.

Completely new UI and all functions. More options. Reports after operations. Now you can choose between a variety of options. It's working for all selected objects.

Bug fixed - Edit Mode while Clean Unused Mats now works.

Crucial update. The Cleaner has a much cleaner code now! New functions and complete simplification. Commands always apply to selected objects. Now the functions are divided into 3 basic items.
Clean Selected - Remove Doubles, Clean Unused Materials, Unify Normals and Clean Custom Split Normals for all selected objects.
Clean Unused Mats - delete unused materials for all selected objects.
Clean Custom Split Normals - delete custom split normals for all selected objects.

Custom split normals added for more objects.

"Remove Unused Materials From Selected Objects" is now also a separate function (this is used very often for data from Revit or SketchUp).